The magnetic force on current-carrying conductors is given by
where
is the current,
is the length of a straight conductor in a uniform magnetic field
, and
is the angle between
and
. The force follows RHR-1 with the thumb in the direction of
.
Conceptual questions
Draw a sketch of the situation in
[link] showing the direction of electrons carrying the current, and use RHR-1 to verify the direction of the force on the wire.
Verify that the direction of the force in an MHD drive, such as that in
[link] , does not depend on the sign of the charges carrying the current across the fluid.
What is the direction of a current that experiences the magnetic force shown in each of the three cases in
[link] , assuming the current runs perpendicular to
?
What is the direction of the magnetic field that produces the magnetic force shown on the currents in each of the three cases in
[link] , assuming
is perpendicular to
?
(a) What is the force per meter on a lightning bolt at the equator that carries 20,000 A perpendicular to the Earth’s
field? (b) What is the direction of the force if the current is straight up and the Earth’s field direction is due north, parallel to the ground?
(a) A DC power line for a light-rail system carries 1000 A at an angle of
to the Earth’s
field. What is the force on a 100-m section of this line? (b) Discuss practical concerns this presents, if any.
(a) 2.50 N
(b) This is about half a pound of force per 100 m of wire, which is much less than the weight of the wire itself. Therefore, it does not cause any special concerns.
What force is exerted on the water in an MHD drive utilizing a 25.0-cm-diameter tube, if 100-A current is passed across the tube that is perpendicular to a 2.00-T magnetic field? (The relatively small size of this force indicates the need for very large currents and magnetic fields to make practical MHD drives.)
A wire carrying a 30.0-A current passes between the poles of a strong magnet that is perpendicular to its field and experiences a 2.16-N force on the 4.00 cm of wire in the field. What is the average field strength?
(a) A 0.750-m-long section of cable carrying current to a car starter motor makes an angle of
with the Earth’s
field. What is the current when the wire experiences a force of
? (b) If you run the wire between the poles of a strong horseshoe magnet, subjecting 5.00 cm of it to a 1.75-T field, what force is exerted on this segment of wire?
(a) What is the angle between a wire carrying an 8.00-A current and the 1.20-T field it is in if 50.0 cm of the wire experiences a magnetic force of 2.40 N? (b) What is the force on the wire if it is rotated to make an angle of
with the field?
The force on the rectangular loop of wire in the magnetic field in
[link] can be used to measure field strength. The field is uniform, and the plane of the loop is perpendicular to the field. (a) What is the direction of the magnetic force on the loop? Justify the claim that the forces on the sides of the loop are equal and opposite, independent of how much of the loop is in the field and do not affect the net force on the loop. (b) If a current of 5.00 A is used, what is the force per tesla on the 20.0-cm-wide loop?
Bacteria doesn't produce energy they are dependent upon their substrate in case of lack of nutrients they are able to make spores which helps them to sustain in harsh environments
_Adnan
But not all bacteria make spores, l mean Eukaryotic cells have Mitochondria which acts as powerhouse for them, since bacteria don't have it, what is the substitution for it?
Assimilatory nitrate reduction is a process that occurs in some microorganisms, such as bacteria and archaea, in which nitrate (NO3-) is reduced to nitrite (NO2-), and then further reduced to ammonia (NH3).
Elkana
This process is called assimilatory nitrate reduction because the nitrogen that is produced is incorporated in the cells of microorganisms where it can be used in the synthesis of amino acids and other nitrogen products
There are nothing like emergency disease but there are some common medical emergency which can occur simultaneously like Bleeding,heart attack,Breathing difficulties,severe pain heart stock.Hope you will get my point .Have a nice day ❣️
_Adnan
define infection ,prevention and control
Innocent
I think infection prevention and control is the avoidance of all things we do that gives out break of infections and promotion of health practices that promote life